Abstract: A master key (K2,2) inputted by an input unit is stored in a storage unit. A matrix generating unit generates key element matrices (M1-M3) with respect to each of split keys (eR2, eR1, eR3) obtained by a key dividing unit dividing the master key (K2,2). To each coordinate entry of the key element matrices (M1-M3), operation data that successively obtained by repeating a hash operation with a one-way hash function is assigned, so as to maintain hierarchical nature of scalability (L). A key generating unit generates partial keys (K1,1-K2,2) corresponding to respective hierarchies of the scalabilities (R, L), on the basis of the key element matrices (M1-M3). These partial keys (K1,1-K2,2) are outputted to a coding unit or a decoding unit by an output unit.

Abstract: The present invention relates to an image processing method and image inspecting method with high versatility which enable efficient and highly accurate proof of authenticity of a digital image. The image processing method subjects at least a part of a digital image which can exist temporarily or continuously in a falsification-vulnerable environment, to a first morphology operation using a predetermined structuring element, to process the digital image. The image inspecting method subjects the digital image thus processed, to a second morphology operation using the same structuring element as in the first morphology operation. The morphology operations have the idempotent and the presence or absence of falsification can be detected by determining identity of images before and after the second morphology operation.

Abstract: A master key (K2,2) inputted by an input unit is stored in a storage unit. A matrix generating unit generates key element matrices (M1-M3) with respect to each of split keys (eR2, eR1, eR3) obtained by a key dividing unit dividing the master key (K2,2). To each coordinate entry of the key element matrices (M1-M3), operation data that successively obtained by repeating a hash operation with a one-way hash function is assigned, so as to maintain hierarchical nature of scalability (L). A key generating unit generates partial keys (K1,1-K2,2) corresponding to respective hierarchies of the scalabilities (R, L), on the basis of the key element matrices (M1-M3). These partial keys (K1,1-K2,2) are outputted to a coding unit or a decoding unit by an output unit.

Abstract: The present invention relates to an image processing method and image inspecting method with high versatility which enable efficient and highly accurate proof of authenticity of a digital image. The image processing method subjects at least a part of a digital image which can exist temporarily or continuously in a falsification-vulnerable environment, to a first morphology operation using a predetermined structuring element, to process the digital image. The image inspecting method subjects the digital image thus processed, to a second morphology operation using the same structuring element as in the first morphology operation. The morphology operations have the idempotent and the presence or absence of falsification can be detected by determining identity of images before and after the second morphology operation.

Abstract: The present invention relates to an encryption key generating method ensuring resistance to collusion attacks and achieving reduction in a key length of encryption keys corresponding to respective hierarchies of each scalability. In the encryption key generating method, an encryption key (K2,2) corresponding to data in the lowest hierarchies of hierarchical scalabilities (R, L) is divided as a master key by the number of hierarchies in scalability (R). Key element matrices (M1-M3) generated with respective split keys (eR2, eR1, eR3) are assigned operation data successively obtained by repeating a hash operation with a one-way hash function, so as to maintain hierarchical nature of scalability (L). Partial keys (K1,1-K2,2) corresponding to respective hierarchies of the scalabilities (R, L) are generated by combining key elements coordinately consistent among the key element matrices (M1-M3).